i3-input: restore input focus on exit() (Thanks f8l)

fixes #641
Merge branch 'i3-input-focus'
Also draw right tab border for split containers (Thanks alex)

fixes #696
Merge branch 'fix-tab-border'
Fix scrolling on a tabbed titlebar which contains split cons (Thanks f8l)

fixes #708
Merge branch 'fix-scroll-split'
Bugfix: Ignore ConfigureRequests for scratchpad windows (Thanks MeanEYE)

fixes #898
Merge branch 'fix-scratch-confreq'
Bugfix: handle MapRequests sent between i3 registering as a wm and handling events

This fixes the problem where i3-nagbar does not come up because its
MapRequest is ignored.

fixes #892
Merge branch 'fix-mapreq'